1. Field of the Invention
The present invention relates to a circuit board for feeding power to an apparatus body, and an image forming apparatus using the circuit board.
2. Description of the Related Art
An electrophotographic color image forming apparatus adopts a method of repeatedly performing plural times a process of transferring onto a recording sheet, a toner image formed on an image bearing member through charging, exposure, and development to form a multi-color superimposed image, and then performing a process of fixing the image to obtain a color image.
In the color image forming apparatus, in the process of performing charging and development, plural high voltages such as a charging voltage and a developing voltage are supplied from a high-voltage circuit board (hereinafter referred to as “high-voltage board”). The high-voltage board has plural contacts so as to electrically connect the plural high voltages to an image forming unit including a charging device, a developing device, a primary transfer roller, and a secondary transfer roller of an apparatus body.
When cables are used for electrically connecting the contacts to the image forming unit, it is necessary to connect the cables to the high-voltage board, and hence, it takes time for connection. Further, cost may increase due to the use of the plural cables. Therefore, as a method of solving the problems, for example, there has been proposed a configuration in which an image forming apparatus body includes spring contacts made of an elastic member in a coil spring shape, and copper foil patterns are formed at predetermined positions on a high-voltage board corresponding to the spring contacts so that the spring contacts are brought into contact with the copper foil patterns on the high-voltage board. When the high-voltage board is mounted to the image forming apparatus body, the spring contacts and the copper foil patterns come into press-contact with each other to be connected electrically (see, for example, Japanese Patent Application Laid-Open No. 2003-195697). Thus, the high-voltage board and the image forming unit can be electrically connected without using cables.
However, the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2003-195697 has the following problems. In the case where solder is not applied to the copper foil patterns serving as contacts on the high-voltage board, the copper foil patterns corrode to cause contact failure between the copper foil patterns and the spring contacts. On the other hand, in the case where solder is applied to the copper foil patterns, the solder contains a highly insulating substance called flux which remains on the surface of the solder when the solder is melted by heating, resulting in contact failure between the copper foil patterns and the spring contacts. In order to remove the flux remaining on the surface, it is necessary to scrape off the flux after melting by heating and to wipe out the flux with alcohol or the like, which complicates the production process of a high-voltage board, leading to an increase in cost.